Midnite Mine Superfund Site Cleanup Update

The Midnite Mine Superfund site is a 350-acre, inactive uranium mine located on the Spokane Indian Reservation. A legacy of the Cold War, uranium mining from 1954 to 1981 left more than 33 million tons of waste rock, unprocessed ore and low-grade ore (also known as protore) laced with contaminants. Contaminants include radionuclides and heavy metals resulting from mining, transport activities and related operations.

EPA reported “great progress” for the 2022 cleanup season. This included: 

  •  “Removal of over 1.3 million cubic yards of waste rock
  • Completed crushing and screening aggregate rock for Pit 3 and the cover for Pit 4
  • Completed the cleanup design for the South Pond
  • Treated 42.1 million gallons of water
  • Started construction on the new water treatment plant”

In April, EPA hosted an in-person and virtual community information meeting. Topics covered included:

  • Scheduled 2023 activities, including construction of the new water treatment plant and the effluent pipeline connection to the Spokane Arm of Lake Roosevelt; completing backfill of Pit 4 and regrading to its final configuration; and dewatering then replacing a leaky liner serving the South Pond.
  • The third Five-Year Review of the Midnite Mine cleanup, which will begin in June. EPA stated the purpose “… is to make sure the selected cleanup actions effectively protect people’s health and the environment.”
  • Completion of the Midnite Mine Superfund Site Community Involvement Plan, which expresses how EPA and the Spokane Tribe will inform and engage with the local community.

Slides and video of the April meeting as well as other Midnite Mine resources can be found on EPA’s website at https://tinyurl.com/yradn2d8.